In integrated circuit (IC) devices, magnetoresistive random access memory (MRAM) is an emerging technology for next generation non-volatile memory devices. MRAM is a memory structure including an array of MRAM cells. A bit of data in each cell is read using resistance, rather than electronic charge. Particularly, each MRAM cell includes a magnetic tunnel junction (MTJ) element, and the resistance of the MTJ element is adjustable to represent logic “0” or logic “1”. The MTJ element includes one ferromagnetic pinned layer and one ferromagnetic free layer separated by a tunneling insulating layer. The resistance of the MTJ element is adjusted by changing a direction of the magnetic moment of the ferromagnetic free layer with respect to that of the ferromagnetic pinned layer. The low and high resistances are utilized to indicate a digital signal “1” or “0”, thereby allowing for data storage.
From an application point of view, MRAM has many advantages. MRAM has a simple cell structure and CMOS logic comparable processes which result in a reduction of the manufacturing complexity and cost in comparison with other non-volatile memory structures. Despite the attractive properties noted above, a number of challenges exist in connection with developing MRAM. Various techniques directed at configurations and materials of these MRAMs have been implemented to try and further improve device performance.